Thiazolidine derivatives and their use

Abstract

A thiazolidine derivatives of the formula: ##STR1## wherein R is a phenyl group having 2 nuclear substituent groups selected from the group consisting of a lower alkyl having 1 to 6 carbon atoms, a lower alkoxy having 1 to 7 carbon atoms, hydroxyl and a carboxylic acyloxy having 1 to 4 carbon atoms, or a phenyl group having a methylenedioxy group in adjacent positions on its ring; R 1 is H or an alkyl having 1 to 6 carbon atoms, or a physiologically acceptable salt thereof is a novel compound having the activity to control certain chronic symptoms due to diabetes, such as diabetic cataract, diabetic neuropathy and diabetic retinosis.

What is claimed is: 
     
       1. A thiazolidine compound of the formula: ##STR31## wherein R is phenyl having 2 nuclear subsituents selected from the group consisting of alkyl having 1 to 6 carbon atoms, alkoxy having 1 to 7 carbon atoms, hydroxyl and carboxylic acyloxy having 1 to 4 carbon atoms, or R is phenyl having a methylenedioxy group in adjacent positions on its ring, and R 1  is hydrogen or alkyl having 1 to 6 carbon atoms,   or a physiologically acceptable salt thereof.   
     
     
       2. A thiazolidine compound as claimed in claim 1, wherein R 1  is hydrogen. 
     
     
       3. A thiazolidine compound as claimed in claim 1, wherein R is a 3,4-dialkoxyphenyl group. 
     
     
       4. A thiazolidine compound as claimed in claim 1, wherein the thiazolidine derivative is 5-(3-ethoxy-4-pentyloxyphenyl)thiazolidine-2,4-dione. 
     
     
       5. A thiazolidine compound as claimed in claim 1, wherein the thiazolidine derivative is 5-(4-butoxy-3-ethoxyphenyl)thiazolidine-2,4-dione. 
     
     
       6. A medicinal composition for the treatment of a mammal suffering from diabetic cataract, diabetic neuropathy or diabetic retinosis, which comprises, (A) as an active ingredient, an effective amount of a compound of the formula: ##STR32## wherein R is phenyl having 2 nuclear substituents selected from the group consisting of alkyl having 1 to 6 carbon atoms, alkoxy having 1 to 7 carbon atoms, hydroxyl and carboxylic acyloxy having 1 to 4 carbon atoms, or R is phenyl having a methylenedioxy group in adjacent positions on its ring, and   R 1  is hydrogen or alkyl having 1 to 6 carbon atoms, or a physiologically acceptable salt thereof, and   (B) a physiologically acceptable carrier, excipient or diluent therefor.   
     
     
       7. A thiazolidine compound as claimed in claim 1, wherein the thiazolidine compound is 5-(3,4-dimethoxyphenyl)thiazolidine-2,4-dione.